IDH1 and glioblastoma: The newly recognized category of «astrocytoma, IDH-mutant, grade 4», separated from the basic category “glioblastoma, grade IV”, had a three times better prognosis compared to “glioblastoma, IDH-wildtype, grade 4” (HR = 0.32; 95% CI: 0.21, 0.51; p < 0.001).